New Build (291)

[Roy Hirshkowitz]

This one introduces two new engines.  Both of these are very experimental at the moment. I may not retain either of them if they don't prove useful.  Although they appear very stable, there may be some hidden bugs.  Be careful using these for production until we have some confidence in their stability and characteristics.  The engines are only accessible via the nXtEngine AutoLisp command use (nXtEngine 2) -OR- (nXtEngine 3).

Both engines include more light pathways than the current product does and can therefore potentially provide more accurate solutions.  Two "tricks" which are used in the first two engines, transparent shadow rays and daylight portals, are not used in these new engines.  This gets rid of two big sources of inaccuracy.  Caustics pathways are automatically included.

Engine 2 can be much less noisy than the Path Tracer for most interiors.  It's convergence, on the other hand,  is not as graceful and will include some discrete artifacts.  It's usually a lot faster than the Path Tracer for interiors.

Engine 3 is a little more accurate than Engine 2, particularly when window coverings are involved.  It converges more gracefully, but slower for some interiors.  It is considerably faster on some exteriors.

Some things to keep in mind with these engines:

• Light leaks in the corners are possible when doing interiors.  Make sure walls, floors and ceilings are modeled as slabs with thickness.
• Both engines start slowly and accelerate.  Pixels/sec should increase as they proceed.
• Using accurate IORs is very important.  IORs of 1.00 should not be used for glass.
• Designating glass as Thick/Thin is more important with these engines.
• Translucency is not implemented.  Allow Surface Roughness is.
• These engines use more memory than the previous two.  64 bit is recommended.  Start your testing and low resolutions.

Let me know what you think-- I'm looking for feedback here.

[Roy Hirshkowitz]

Nice.

[Roy Hirshkowitz]

Night shots from distance may be difficult with the new engines.

[akinlolu olugboji]

Day shots on engine 3 has lots of spots must be due to the shininess of the wall tiles, same on cars too.

[Roy Hirshkowitz]

It's hard to say-- you need to let it run longer.  Engine 2 is not exhibiting any light leaks, those are other artifacts.  I would try that one for a while and see how it does.

[Roy Hirshkowitz]

With engine 3, all indirect lighting uses photon mapping, hence the spots that gradually resolve.  With engine 2, only caustic paths use photon mapping.  Try using engine 2 for this one and let it run a bit.

[Miguel Tano Adanes]

Hi Roy, I'm experimenting new engines with the room model (remeber?). Well, engine 2 crashes when finishes loading the model and autocad shuts down. Engine 3 works pretty fine.

[Roy Hirshkowitz]

What was the name of the model?

[Miguel Tano Adanes]

it was "stanza_tootal_NOCHE_bj.dwg". I uploaded it as "stanza_out" in several zip files.

[Alejandro Testa]

Win 7 pro. 64 bits.  Autocad 2011. Engine 2 crashes Engine 3 is running.

[Roy Hirshkowitz]

Can you upload the model?

[Alejandro Testa]

File already uploaded

[Roy Hirshkowitz]

The crash is occurring on models with more than 32 lights.  I've got it fixed and am letting yours run for a bit.  I'll update soon.